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Why were 3D games on the Amiga not faster than on similar 16 bit systems like the Atari ST
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It seems that 3D games, especially simulations like Falcon, were not faster (fps) on the Amiga than on the Atari ST - even a bit slower due to the CPU clock.
I was wondering why this is the case, since the Agnus seems to me as an early model of a GPU, capable of drawing vector lines and even fill out polygons. Was it not capable to display the typical number of 3D objects in those games or what was it simply not used, since it would require a complete different codeline for the Amiga with respect to 3D rendering ?
amiga
asked 5 hours ago
Marco
527139
 |Â
show 1 more comment
up vote
5
down vote
favorite
It seems that 3D games, especially simulations like Falcon, were not faster (fps) on the Amiga than on the Atari ST - even a bit slower due to the CPU clock.
I was wondering why this is the case, since the Agnus seems to me as an early model of a GPU, capable of drawing vector lines and even fill out polygons. Was it not capable to display the typical number of 3D objects in those games or what was it simply not used, since it would require a complete different codeline for the Amiga with respect to 3D rendering ?
amiga
asked 5 hours ago
Marco
527139
What does "faster" mean? more frames per second or something?
– Wilson
4 hours ago
yes, more fps, I update the question
– Marco
3 hours ago
Mind to support your assumption with some data? Link frame rates used and how they differ?
– Raffzahn
1 hour ago
1
That is a little tough for me, since I did not the comparison by myself. I have a print magazine from 1990, which only covered simulations cross-system and there almost was for every game the statement that the 3D aspects between Amiga and Atari ST would be more or less the same
– Marco
38 mins ago
Keep in mind that 3D isn't anything that was hardware related (non CPU that is). Also, these machines where rather 'hard-coded' Timing was made to fit the 50/60 Hz fixed frame rate, not independant units operating and synchronizing as of today - and related, without all the inbetween layers. So unless special effects of the amiga where used, it all comes down to the CPU manipulating the bitmap. And when used, these games where usually not portable in any way.
– Raffzahn
19 mins ago
 |Â
show 1 more comment
up vote
5
down vote
favorite
up vote
5
down vote
favorite
It seems that 3D games, especially simulations like Falcon, were not faster (fps) on the Amiga than on the Atari ST - even a bit slower due to the CPU clock.
I was wondering why this is the case, since the Agnus seems to me as an early model of a GPU, capable of drawing vector lines and even fill out polygons. Was it not capable to display the typical number of 3D objects in those games or what was it simply not used, since it would require a complete different codeline for the Amiga with respect to 3D rendering ?
amiga
asked 5 hours ago
Marco
527139
It seems that 3D games, especially simulations like Falcon, were not faster (fps) on the Amiga than on the Atari ST - even a bit slower due to the CPU clock.
I was wondering why this is the case, since the Agnus seems to me as an early model of a GPU, capable of drawing vector lines and even fill out polygons. Was it not capable to display the typical number of 3D objects in those games or what was it simply not used, since it would require a complete different codeline for the Amiga with respect to 3D rendering ?
amiga
amiga
asked 5 hours ago
Marco
527139
asked 5 hours ago
Marco
527139
edited 3 hours ago
asked 5 hours ago
Marco
527139
asked 5 hours ago
Marco
527139
asked 5 hours ago
Marco
527139
527139
What does "faster" mean? more frames per second or something?
– Wilson
4 hours ago
yes, more fps, I update the question
– Marco
3 hours ago
Mind to support your assumption with some data? Link frame rates used and how they differ?
– Raffzahn
1 hour ago
1
That is a little tough for me, since I did not the comparison by myself. I have a print magazine from 1990, which only covered simulations cross-system and there almost was for every game the statement that the 3D aspects between Amiga and Atari ST would be more or less the same
– Marco
38 mins ago
Keep in mind that 3D isn't anything that was hardware related (non CPU that is). Also, these machines where rather 'hard-coded' Timing was made to fit the 50/60 Hz fixed frame rate, not independant units operating and synchronizing as of today - and related, without all the inbetween layers. So unless special effects of the amiga where used, it all comes down to the CPU manipulating the bitmap. And when used, these games where usually not portable in any way.
– Raffzahn
19 mins ago
 |Â
show 1 more comment
What does "faster" mean? more frames per second or something?
– Wilson
4 hours ago
yes, more fps, I update the question
– Marco
3 hours ago
Mind to support your assumption with some data? Link frame rates used and how they differ?
– Raffzahn
1 hour ago
1
That is a little tough for me, since I did not the comparison by myself. I have a print magazine from 1990, which only covered simulations cross-system and there almost was for every game the statement that the 3D aspects between Amiga and Atari ST would be more or less the same
– Marco
38 mins ago
Keep in mind that 3D isn't anything that was hardware related (non CPU that is). Also, these machines where rather 'hard-coded' Timing was made to fit the 50/60 Hz fixed frame rate, not independant units operating and synchronizing as of today - and related, without all the inbetween layers. So unless special effects of the amiga where used, it all comes down to the CPU manipulating the bitmap. And when used, these games where usually not portable in any way.
– Raffzahn
19 mins ago
What does "faster" mean? more frames per second or something?
– Wilson
4 hours ago
What does "faster" mean? more frames per second or something?
– Wilson
4 hours ago
yes, more fps, I update the question
– Marco
3 hours ago
yes, more fps, I update the question
– Marco
3 hours ago
Mind to support your assumption with some data? Link frame rates used and how they differ?
– Raffzahn
1 hour ago
Mind to support your assumption with some data? Link frame rates used and how they differ?
– Raffzahn
1 hour ago
1
1
That is a little tough for me, since I did not the comparison by myself. I have a print magazine from 1990, which only covered simulations cross-system and there almost was for every game the statement that the 3D aspects between Amiga and Atari ST would be more or less the same
– Marco
38 mins ago
That is a little tough for me, since I did not the comparison by myself. I have a print magazine from 1990, which only covered simulations cross-system and there almost was for every game the statement that the 3D aspects between Amiga and Atari ST would be more or less the same
– Marco
38 mins ago
Keep in mind that 3D isn't anything that was hardware related (non CPU that is). Also, these machines where rather 'hard-coded' Timing was made to fit the 50/60 Hz fixed frame rate, not independant units operating and synchronizing as of today - and related, without all the inbetween layers. So unless special effects of the amiga where used, it all comes down to the CPU manipulating the bitmap. And when used, these games where usually not portable in any way.
– Raffzahn
19 mins ago
Keep in mind that 3D isn't anything that was hardware related (non CPU that is). Also, these machines where rather 'hard-coded' Timing was made to fit the 50/60 Hz fixed frame rate, not independant units operating and synchronizing as of today - and related, without all the inbetween layers. So unless special effects of the amiga where used, it all comes down to the CPU manipulating the bitmap. And when used, these games where usually not portable in any way.
– Raffzahn
19 mins ago
 |Â
show 1 more comment
2 Answers
2
active
oldest
votes
up vote
5
down vote
accepted
There are a few reasons why multi-platform 3D games turned out to be no faster on the Amiga than on other 68000-based platforms without its blitter:
The developers may have targetted the lowest common denominator system and not taken advantage of the blitter when they ported to the Amiga. Early games and poor conversions tended to be like this.
A naive implementation by somebody unfamiliar with the hardware may well fail to use the blitter's line-drawing and space-filling operations efficiently, thus losing the benefit. If one draws and fills individual polygons and then blits them to the framebuffer, that is a lot of wasteful work. AmigaOS itself didn't set a good example here.
Finally, the blitter is a pure 2D device which offers no acceleration for 3D calculations, so the main CPU needs to do those. This involves a lot of matrix multiplication, and the 68000's MULU/MULS instructions are very slow, taking about 70 cycles. (The exact number of cycles is data-dependent because the microcode uses an iterative algorithm.) At 7.09MHz that's a shade over 100,000 multiplies per second, or 20,000 per 50Hz field. Even if the blitter was infinitely-fast, this still sets an upper limit of a few hundred points on screen or compromise on frame rate.
answered 2 hours ago
pndc
5,44722439
thx for the explanations...I have not thought about the necessary matrix stuff and that of crs makes completely sense, then
– Marco
36 mins ago
add a comment |Â
up vote
2
down vote
The thing the Agnus has that speeds up 3D games is the polygon fill feature. Blitting by itself is not so much a standard operation driving 3D performance. It can help 2D games and windowed GUIs a lot, however, one of the reasons the Atari ST got a (much simpler) blitter as well in later releases.
3D Games are CPU-heavy, or rather performance is driven how fast you can do vector arithmetics and trigonometric functions (which would mainly be done by table lookups in older games) - Agnus doesn't help here, even a 68881 wouldn't help much, as fixed-point integer maths done by a 68k are still faster. We're talking mainly integer operations here, and that is driven by raw CPU speed and bus contention.
answered 22 mins ago
tofro
12k32570
add a comment |Â
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
5
down vote
accepted
There are a few reasons why multi-platform 3D games turned out to be no faster on the Amiga than on other 68000-based platforms without its blitter:
The developers may have targetted the lowest common denominator system and not taken advantage of the blitter when they ported to the Amiga. Early games and poor conversions tended to be like this.
A naive implementation by somebody unfamiliar with the hardware may well fail to use the blitter's line-drawing and space-filling operations efficiently, thus losing the benefit. If one draws and fills individual polygons and then blits them to the framebuffer, that is a lot of wasteful work. AmigaOS itself didn't set a good example here.
Finally, the blitter is a pure 2D device which offers no acceleration for 3D calculations, so the main CPU needs to do those. This involves a lot of matrix multiplication, and the 68000's MULU/MULS instructions are very slow, taking about 70 cycles. (The exact number of cycles is data-dependent because the microcode uses an iterative algorithm.) At 7.09MHz that's a shade over 100,000 multiplies per second, or 20,000 per 50Hz field. Even if the blitter was infinitely-fast, this still sets an upper limit of a few hundred points on screen or compromise on frame rate.
answered 2 hours ago
pndc
5,44722439
thx for the explanations...I have not thought about the necessary matrix stuff and that of crs makes completely sense, then
– Marco
36 mins ago
add a comment |Â
up vote
5
down vote
accepted
There are a few reasons why multi-platform 3D games turned out to be no faster on the Amiga than on other 68000-based platforms without its blitter:
The developers may have targetted the lowest common denominator system and not taken advantage of the blitter when they ported to the Amiga. Early games and poor conversions tended to be like this.
A naive implementation by somebody unfamiliar with the hardware may well fail to use the blitter's line-drawing and space-filling operations efficiently, thus losing the benefit. If one draws and fills individual polygons and then blits them to the framebuffer, that is a lot of wasteful work. AmigaOS itself didn't set a good example here.
Finally, the blitter is a pure 2D device which offers no acceleration for 3D calculations, so the main CPU needs to do those. This involves a lot of matrix multiplication, and the 68000's MULU/MULS instructions are very slow, taking about 70 cycles. (The exact number of cycles is data-dependent because the microcode uses an iterative algorithm.) At 7.09MHz that's a shade over 100,000 multiplies per second, or 20,000 per 50Hz field. Even if the blitter was infinitely-fast, this still sets an upper limit of a few hundred points on screen or compromise on frame rate.
answered 2 hours ago
pndc
5,44722439
thx for the explanations...I have not thought about the necessary matrix stuff and that of crs makes completely sense, then
– Marco
36 mins ago
add a comment |Â
up vote
5
down vote
accepted
up vote
5
down vote
accepted
There are a few reasons why multi-platform 3D games turned out to be no faster on the Amiga than on other 68000-based platforms without its blitter:
The developers may have targetted the lowest common denominator system and not taken advantage of the blitter when they ported to the Amiga. Early games and poor conversions tended to be like this.
A naive implementation by somebody unfamiliar with the hardware may well fail to use the blitter's line-drawing and space-filling operations efficiently, thus losing the benefit. If one draws and fills individual polygons and then blits them to the framebuffer, that is a lot of wasteful work. AmigaOS itself didn't set a good example here.
Finally, the blitter is a pure 2D device which offers no acceleration for 3D calculations, so the main CPU needs to do those. This involves a lot of matrix multiplication, and the 68000's MULU/MULS instructions are very slow, taking about 70 cycles. (The exact number of cycles is data-dependent because the microcode uses an iterative algorithm.) At 7.09MHz that's a shade over 100,000 multiplies per second, or 20,000 per 50Hz field. Even if the blitter was infinitely-fast, this still sets an upper limit of a few hundred points on screen or compromise on frame rate.
answered 2 hours ago
pndc
5,44722439
There are a few reasons why multi-platform 3D games turned out to be no faster on the Amiga than on other 68000-based platforms without its blitter:
The developers may have targetted the lowest common denominator system and not taken advantage of the blitter when they ported to the Amiga. Early games and poor conversions tended to be like this.
A naive implementation by somebody unfamiliar with the hardware may well fail to use the blitter's line-drawing and space-filling operations efficiently, thus losing the benefit. If one draws and fills individual polygons and then blits them to the framebuffer, that is a lot of wasteful work. AmigaOS itself didn't set a good example here.
Finally, the blitter is a pure 2D device which offers no acceleration for 3D calculations, so the main CPU needs to do those. This involves a lot of matrix multiplication, and the 68000's MULU/MULS instructions are very slow, taking about 70 cycles. (The exact number of cycles is data-dependent because the microcode uses an iterative algorithm.) At 7.09MHz that's a shade over 100,000 multiplies per second, or 20,000 per 50Hz field. Even if the blitter was infinitely-fast, this still sets an upper limit of a few hundred points on screen or compromise on frame rate.
answered 2 hours ago
pndc
5,44722439
answered 2 hours ago
pndc
5,44722439
answered 2 hours ago
pndc
5,44722439
answered 2 hours ago
pndc
5,44722439
5,44722439
thx for the explanations...I have not thought about the necessary matrix stuff and that of crs makes completely sense, then
– Marco
36 mins ago
add a comment |Â
thx for the explanations...I have not thought about the necessary matrix stuff and that of crs makes completely sense, then
– Marco
36 mins ago
thx for the explanations...I have not thought about the necessary matrix stuff and that of crs makes completely sense, then
– Marco
36 mins ago
thx for the explanations...I have not thought about the necessary matrix stuff and that of crs makes completely sense, then
– Marco
36 mins ago
add a comment |Â
up vote
2
down vote
The thing the Agnus has that speeds up 3D games is the polygon fill feature. Blitting by itself is not so much a standard operation driving 3D performance. It can help 2D games and windowed GUIs a lot, however, one of the reasons the Atari ST got a (much simpler) blitter as well in later releases.
3D Games are CPU-heavy, or rather performance is driven how fast you can do vector arithmetics and trigonometric functions (which would mainly be done by table lookups in older games) - Agnus doesn't help here, even a 68881 wouldn't help much, as fixed-point integer maths done by a 68k are still faster. We're talking mainly integer operations here, and that is driven by raw CPU speed and bus contention.
answered 22 mins ago
tofro
12k32570
add a comment |Â
up vote
2
down vote
The thing the Agnus has that speeds up 3D games is the polygon fill feature. Blitting by itself is not so much a standard operation driving 3D performance. It can help 2D games and windowed GUIs a lot, however, one of the reasons the Atari ST got a (much simpler) blitter as well in later releases.
3D Games are CPU-heavy, or rather performance is driven how fast you can do vector arithmetics and trigonometric functions (which would mainly be done by table lookups in older games) - Agnus doesn't help here, even a 68881 wouldn't help much, as fixed-point integer maths done by a 68k are still faster. We're talking mainly integer operations here, and that is driven by raw CPU speed and bus contention.
answered 22 mins ago
tofro
12k32570
add a comment |Â
up vote
2
down vote
up vote
2
down vote
The thing the Agnus has that speeds up 3D games is the polygon fill feature. Blitting by itself is not so much a standard operation driving 3D performance. It can help 2D games and windowed GUIs a lot, however, one of the reasons the Atari ST got a (much simpler) blitter as well in later releases.
3D Games are CPU-heavy, or rather performance is driven how fast you can do vector arithmetics and trigonometric functions (which would mainly be done by table lookups in older games) - Agnus doesn't help here, even a 68881 wouldn't help much, as fixed-point integer maths done by a 68k are still faster. We're talking mainly integer operations here, and that is driven by raw CPU speed and bus contention.
answered 22 mins ago
tofro
12k32570
The thing the Agnus has that speeds up 3D games is the polygon fill feature. Blitting by itself is not so much a standard operation driving 3D performance. It can help 2D games and windowed GUIs a lot, however, one of the reasons the Atari ST got a (much simpler) blitter as well in later releases.
3D Games are CPU-heavy, or rather performance is driven how fast you can do vector arithmetics and trigonometric functions (which would mainly be done by table lookups in older games) - Agnus doesn't help here, even a 68881 wouldn't help much, as fixed-point integer maths done by a 68k are still faster. We're talking mainly integer operations here, and that is driven by raw CPU speed and bus contention.
answered 22 mins ago
tofro
12k32570
answered 22 mins ago
tofro
12k32570
answered 22 mins ago
tofro
12k32570
answered 22 mins ago
tofro
12k32570
12k32570
add a comment |Â
add a comment |Â
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What does "faster" mean? more frames per second or something?
– Wilson
4 hours ago
yes, more fps, I update the question
– Marco
3 hours ago
Mind to support your assumption with some data? Link frame rates used and how they differ?
– Raffzahn
1 hour ago
1
That is a little tough for me, since I did not the comparison by myself. I have a print magazine from 1990, which only covered simulations cross-system and there almost was for every game the statement that the 3D aspects between Amiga and Atari ST would be more or less the same
– Marco
38 mins ago
Keep in mind that 3D isn't anything that was hardware related (non CPU that is). Also, these machines where rather 'hard-coded' Timing was made to fit the 50/60 Hz fixed frame rate, not independant units operating and synchronizing as of today - and related, without all the inbetween layers. So unless special effects of the amiga where used, it all comes down to the CPU manipulating the bitmap. And when used, these games where usually not portable in any way.
– Raffzahn
19 mins ago